Production of canola protein product without heat treatment (“C200CaC”)

ABSTRACT

The supernatant from the deposition of canola protein micellar mass is processed to provide a canola protein product having a protein content of about 60 to less than about 90 wt % (N×6.25) protein on a dry weight basis and which is soluble in an aqueous acidic environment.

REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Phase filing under 35 USC 371 ofInternational Application No. PCT/CA2010/000633 filed Apr. 23, 2010,which in time, claims priority under 35 USC 119(e) from U.S. ProvisionalPatent Application No. 61/213,181 filed May 14, 2009.

FIELD OF INVENTION

The invention relates to the production of a canola protein product.

BACKGROUND TO THE INVENTION

In copending U.S. patent application Ser. No. 12/542,922 filed Aug. 18,2009 (7865-402), assigned to the assignee hereof and the disclosure ofwhich is incorporated herein by reference, there is described theproduction of a canola protein isolate which has solubility over a widerange of acid pH values and clarity in aqueous medium, making itpossible, for example, to prepare protein fortified beverages,particularly at acid pH values, in which the clarity is not impaired bythe addition of the canola protein isolate.

The procedure used in the prior U.S. application Ser. No. 12/542,922,involves adding calcium chloride to supernatant from the precipitationof a canola protein micellar mass to provide a conductivity of about 5mS to about 30 mS, preferably about 8 to about 10 mS, removing theprecipitated phytate material from the resulting solution to leave aclear solution, optionally adjusting the pH of the clear solution toabout 2.0 to about 4.0, preferably about 2.9 to about 3.2, such as bythe addition of hydrochloric acid, concentrating the optionallypH-adjusted clear solution to a protein content of about 50 to about 500g/L, preferably about 100 to about 250 g/L, to produce a clearconcentrated canola protein solution, optionally diafiltering the clearconcentrated canola protein solution, such as with volumes of pH 3water, optionally effecting a colour removal step, such as a granularactivated carbon treatment, and drying the concentrated solution.

This prior application describes the product as a canola proteinisolate, i.e. a canola protein product which contains at least 90 wt %(N×6.25) on a dry weight basis.

Canola is also known as rapeseed or oil seed rape.

SUMMARY OF THE INVENTION

It has now been found that, if the procedure described in theaforementioned U.S. Ser. No. 12/542,922, is effected in such a mannerthat the resulting canola protein product contains less than about 90 wt% (N×6.25) d.b. protein, such as at least about 60 wt % (N×6.25), theconcentration at which the product is considered to be a concentrate,there is obtained a canola protein product which performssatisfactorily. This result is achieved herein by omitting thediafiltration step or by stopping the ultrafiltration step earlier, sothat lesser amounts of impurities are removed during these steps.

In accordance with one aspect of the present invention, there isprovided a process of preparing a canola protein product, whichcomprises:

-   -   adding a calcium salt, preferably calcium chloride, to        supernatant from the precipitation of a canola protein micellar        mass to provide a conductivity of about 5 mS to about 30 mS,        preferably about 8 to about 10 mS, to form a calcium phytate        precipitate,    -   removing precipitated calcium phytate from the resulting        solution to provide a clear solution,    -   optionally adjusting the pH of the clear solution to about 2.0        to about 4.0, preferably about 2.9 to about 3.2, such as by the        addition of hydrochloric acid,    -   concentrating the optionally pH-adjusted clear solution to a        protein content of at least about 50 g/L, preferably about 50 to        about 500 g/L, more preferably about 100 to about 250 g/L, to        produce a clear concentrated canola protein solution,    -   optionally diafiltering the clear concentrated canola protein        solution, such as with volumes of pH 3 or natural pH water,    -   optionally effecting a colour removal step, such as a granular        activated carbon treatment, and    -   drying the concentrated protein solution to produce a dried        canola protein product,        wherein said concentration and/or optional diafiltration step        are effected in such manner that the dried canola protein        product contains about 60 to less than 90 wt % (N×6.25) protein        on a dry weight basis.

The supernatant may be partially concentrated to an intermediateconcentration prior to addition of the calcium salt. The precipitatewhich forms is removed and the resulting solution is acidified asdescribed above, further concentrated to the final concentration andthen optionally diafiltered and dried.

Alternatively, the supernatant first may be concentrated to the finalconcentration, the calcium salt is added to the concentratedsupernatant, the resulting precipitate is removed and the solution isacidified and then optionally diafiltered and dried.

In another variation of the above-described process, initially a smallamount of calcium salt is added to the supernatant such that noprecipitate is formed, the solution is acidified and partiallyconcentrated to an intermediate concentration, an additional amount ofcalcium salt is added to the partially concentrated supernatant and aprecipitate forms.

The precipitate is removed and the solution is concentrated to its finalconcentration and optionally diafiltered and dried.

It is an option in the above-described procedures to omit the removal ofthe precipitate, which leads to a higher phytate content in the product.In such procedure, the calcium salt is added to supernatant, partiallyconcentrated supernatant or fully concentrated supernatant and theprecipitate is not removed. Acidification leads to resolubilization ofthe precipitate.

A further option is to omit the acidification and effect processing ofthe solution at natural pH. In this option calcium salt is added tosupernatant, partially concentrated supernatant or concentratedsupernatant to form a precipitate which is removed. The resultingsolution then is processed as described above without the acidificationstep.

Where the supernatant is partially concentrated prior to the addition ofthe calcium salt and fully concentrated after removal of theprecipitate, the supernatant is first concentrated to a proteinconcentration of about 50 g/L or less, and, after removal of theprecipitate, then is concentrated to a concentration of at least about50 g/L, preferably about 50 to about 500 g/L, more preferably about 100to about 250 g/L.

In one embodiment of the invention, the calcium salt may be added in twostages. In this embodiment, a small amount of calcium is added to thesupernatant to provide a conductivity of about 1 mS to about 3.5 mS,preferably about 1 mS to about 2 mS, which is insufficient to cause theformation of a precipitate.

The resulting solution is acidified and partially concentrated under theconditions described above. The balance of the calcium salt is added tothe partially concentrated solution to provide a conductivity of about 4mS to about 30 mS, preferably about 4 to about 10 mS, to result in theformation of a precipitate. The precipitate then is removed. Theresulting clear solution then is concentrated under the conditionsdescribed above.

The canola protein product produced according to the processes hereinare suitable, not only for protein fortification of acidic media but maybe used in conventional applications protein isolates, including, butnot limited to, protein fortification of processed foods and beverages,emulsification of oils, as a body former in baked goods and foamingagent in products which entrap gases. In addition, the canola proteinproduct may be formed into protein fibers, useful in meat analogs, andmay be used as an egg white substitute or extender in food productswhere egg white is used as a binder. The canola protein product may beused as nutritional supplements. Other uses of the canola proteinproduct are in pets foods, animal feed and in industrial and cosmeticapplications and in personal care products.

GENERAL DESCRIPTION OF THE INVENTION

The initial step of the process of providing the canola protein productinvolves solubilizing proteinaceous material from canola oil seed meal.The proteinaceous material recovered from canola seed meal may be theprotein naturally occurring in canola seed or the proteinaceous materialmay be a protein modified by genetic manipulation but possessingcharacteristic hydrophobic and polar properties of the natural protein.The canola meal may be any canola meal resulting from the removal ofcanola oil from canola oil seed with varying levels of non-denaturedprotein, resulting, for example, from hot hexane extraction or cold oilextrusion methods. The removal of canola oil from canola oil seedusually is effected as a separate operation from the protein isolaterecovery procedure described herein.

Protein solubilization is effected most efficiently by using a foodgrade salt solution since the presence of the salt enhances the removalof soluble protein from the oil seed meal. Where the canola proteinisolate is intended for non-food uses, non-food-grade chemicals may beused. The salt usually is sodium chloride, although other salts, suchas, potassium chloride, may be used. The salt solution has an ionicstrength of at least about 0.05, preferably at least about 0.10, toenable solubilization of significant quantities of protein to beeffected. As the ionic strength of the salt solution increases, thedegree of solubilization of protein in the oil seed meal initiallyincreases until a maximum value is achieved. Any subsequent increase inionic strength does not increase the total protein solubilized. Theionic strength of the food grade salt solution which causes maximumprotein solubilization varies depending on the salt concerned and theoil seed meal chosen.

In view of the greater degree of dilution required for proteinprecipitation with increasing ionic strengths, it is usually preferredto utilize an ionic strength value less than about 0.8, and morepreferably a value of about 0.1 to about 0.15.

In a batch process, the salt solubilization of the protein is effectedat a temperature of from about 5° C. to about 75° C., preferablyaccompanied by agitation to decrease the solubilization time, which isusually about 10 to about 60 minutes. It is preferred to effect thesolubilization to extract substantially as much protein from the oilseed meal as is practicable, so as to provide an overall high productyield.

The lower temperature limit of about 5° C. is chosen sincesolubilization is impracticably slow below this temperature while theupper preferred temperature limit of about 75° C. is chosen due to thedenaturation temperature of some of the present proteins.

In a continuous process, the extraction of the protein from the canolaoil seed meal is carried out in any manner consistent with effecting acontinuous extraction of protein from the canola oil seed meal. In oneembodiment, the canola oil seed meal is continuously mixed with a foodgrade salt solution and the mixture is conveyed through a pipe orconduit having a length and at a flow rate for a residence timesufficient to effect the desired extraction in accordance with theparameters described herein. In such continuous procedure, the saltsolubilization step is effected rapidly, in a time of up to about 10minutes, preferably to effect solubilization to extract substantially asmuch protein from the canola oil seed meal as is practicable. Thesolubilization in the continuous procedure is effected at temperaturesbetween about 10° C. and about 75° C., preferably between about 15° C.and about 35° C.

The aqueous food grade salt solution generally has a pH of about 5 toabout 6.8, preferably about 5.3 to about 6.2, the pH of the saltsolution may be adjusted to any desired value within the range of about5 to about 6.8 for use in the extraction step by the use of anyconvenient acid, usually hydrochloric acid, or alkali, usually sodiumhydroxide, as required.

The concentration of oil seed meal in the food grade salt solutionduring the solubilization step may vary widely. Typical concentrationvalues are about 5 to about 15% w/v.

The protein extraction step with the aqueous salt solution has theadditional effect of solubilizing fats which may be present in thecanola meal, which then results in the fats being present in the aqueousphase.

The protein solution resulting from the extraction step generally has aprotein concentration of about 5 to about 40 g/L, preferably about 10 toabout 30 g/L.

The aqueous salt solution may contain an antioxidant. The antioxidantmay be any convenient antioxidant, such as sodium sulfite or ascorbicacid. The quantity of antioxidant employed may vary from about 0.01 toabout 1 wt % of the solution, preferably about 0.05 wt %. Theantioxidant serves to inhibit oxidation of phenolics in the proteinsolution.

The aqueous phase resulting from the extraction step then may beseparated from the residual canola meal, in any convenient manner, suchas by employing a decanter centrifuge, followed by disc centrifugationand/or filtration to remove residual meal. The separated residual mealmay be dried for disposal.

The colour of the final canola protein product can be improved in termsof light colour and less intense yellow by the mixing of powderedactivated carbon or other pigment adsorbing agent with the separatedaqueous protein solution and subsequently removing the adsorbent,conveniently by filtration, to provide a protein solution. Diafiltrationalso may be used for pigment removal.

Such pigment removal step may be carried out under any convenientconditions, generally at the ambient temperature of the separatedaqueous protein solution, employing any suitable pigment adsorbingagent. For powdered activated carbon, an amount of about 0.025% to about5% w/v, preferably about 0.05% to about 2% w/v, is employed.

Where the canola seed meal contains significant quantities of fat, asdescribed in U.S. Pat. Nos. 5,844,086 and 6,005,076, assigned to theassignee hereof and the disclosures of which are incorporated herein byreference, then the defatting steps described therein may be effected onthe separated aqueous protein solution and on the concentrated aqueousprotein solution discussed below. When the colour improvement step iscarried out, such step may be effected after the first defatting step.

As an alternative to extracting the oil seed meal with an aqueous saltsolution, such extraction may be made using water alone, although theutilization of water alone tends to extract less protein from the oilseed meal than the aqueous salt solution. Where such alternative isemployed, then the salt, in the concentrations discussed above, may beadded to the protein solution after separation from the residual oilseed meal in order to maintain the protein in solution during theconcentration step described below. When a first fat removal step iscarried out, the salt generally is added after completion of suchoperations.

Another alternative procedure is to extract the oil seed meal with thefood grade salt solution at a relatively high pH value above about 6.8,generally up to about 9.9. The pH of the food grade salt solution may beadjusted to the desired alkaline value by the use of any convenientfood-grade alkali, such as aqueous sodium hydroxide solution.Alternatively, the oil seed meal may be extracted with the salt solutionat a relatively low pH below about pH 5, generally down to about pH 3.Where such alternative is employed, the aqueous phase resulting from theoil seed meal extraction step then is separated from the residual canolameal, in any convenient manner, such as by employing decantercentrifugation, followed by disc centrifugation and/or filtration toremove residual meal. The separated residual meal may be dried fordisposal.

The aqueous protein solution resulting from the high or low pHextraction step then is pH adjusted to the range of about 5 to about6.8, preferably about 5.3 to about 6.2, as discussed above, prior tofurther processing as discussed below. Such pH adjustment may beeffected using any convenient acid, such as hydrochloric acid, oralkali, such as sodium hydroxide, as appropriate.

The aqueous protein solution is concentrated to increase the proteinconcentration thereof while maintaining the ionic strength thereofsubstantially constant. Such concentration generally is effected toprovide a concentrated protein solution having a protein concentrationof at least about 50 g/L, preferably at least about 200 g/L, morepreferably at least about 250 g/L.

The concentration step may be effected in any convenient mannerconsistent with batch or continuous operation, such as by employing anyconvenient selective membrane technique, such as ultrafiltration ordiafiltration, using membranes, such as hollow-fibre membranes orspiral-wound membranes, with a suitable molecular weight cut-off, suchas about 3,000 to about 100,000 daltons, preferably about 5,000 to about10,000 daltons, having regard to differing membrane materials andconfigurations, and, for continuous operation, dimensioned to permit thedesired degree of concentration as the aqueous protein solution passesthrough the membranes.

As is well known, ultrafiltration and similar selective membranetechniques permit low molecular weight species to pass through themembrane while preventing higher molecular weight species from so doing.The low molecular weight species include not only the ionic species ofthe food grade salt but also low molecular weight materials extractedfrom the source material, such as, carbohydrates, pigments andanti-nutritional factors, as well as any low molecular weight forms ofthe protein. The molecular weight cut-off of the membrane is usuallychosen to ensure retention of a significant proportion of the protein inthe solution, while permitting contaminants to pass through havingregard to the different membrane materials and configurations.

The concentrated protein solution then may be subjected to adiafiltration step using an aqueous salt solution of the same molarityand pH as the extraction solution. Such diafiltration may be effectedusing from about 2 to about 20 volumes of diafiltration solution,preferably about 5 to about 10 volumes of diafiltration solution. In thediafiltration operation, further quantities of contaminants are removedfrom the aqueous protein solution by passage through the membrane withthe permeate. The diafiltration operation may be effected until nosignificant further quantities of contaminants and visible colour arepresent in the permeate. Such diafiltration may be effected using thesame membrane as for the concentration step. However, if desired, thediafiltration step may be effected using a separate membrane with adifferent molecular weight cut-off, such as a membrane having amolecular weight cut-off in the range of about 3,000 to about 100,000daltons, preferably about 5,000 to about 10,000 daltons, having regardto different membrane materials and configuration.

An antioxidant may be present in the diafiltration medium during atleast part of the diafiltration step. The antioxidant may be anyconvenient antioxidant, such as sodium sulfite or ascorbic acid. Thequantity of antioxidant employed in the diafiltration medium depends onthe materials employed and may vary from about 0.01 to about 1 wt %,preferably about 0.05 wt %. The antioxidant serves to inhibit oxidationof phenolics present in the concentrated canola protein isolatesolution.

The concentration step and the diafiltration step may be effected at anyconvenient temperature, generally about 20° to about 60° C., preferablyabout 20° to about 30° C., and for the period of time to effect thedesired degree of concentration. The temperature and other conditionsused to some degree depend upon the membrane equipment used to effectthe concentration and the desired protein concentration of the solution.

The concentrated and optionally diafiltered protein solution may besubject to a further defatting operation, if required, as described inU.S. Pat. Nos. 5,844,086 and 6,005,076.

The concentrated and optionally diafiltered protein solution may besubject to a colour removal operation as an alternative to the colourremoval operation described above. Powdered activated carbon may be usedherein as well as granulated activated carbon (GAC). Another materialwhich may be used as a colour adsorbing agent is polyvinyl pyrrolidone.

The colour adsorbing agent treatment step may be carried out under anyconvenient conditions, generally at the ambient temperature of thecanola protein solution. For powdered activated carbon, an amount ofabout 0.025% to about 5% w/v, preferably about 0.05% to about 2% w/v,may be used. Where polyvinylpyrrolidone is used as the colour adsorbingagent, an amount of about 0.5% to about 5% w/v, preferably about 2% toabout 3% w/v, may be used. The colour adsorbing agent may be removedfrom the canola protein solution by any convenient means, such as byfiltration.

The concentrated and optionally diafiltered protein solution resultingfrom the optional colour removal step may be subjected to pasteurizationto reduce the microbial load. Such pasteurization may be effected underany desired pasteurization conditions. Generally, the concentrated andoptionally diafiltered protein solution is heated to a temperature ofabout 55° to about 70° C., preferably about 60° to about 65° C., forabout 10 to about 15 minutes, preferably about 10 minutes. Thepasteurized concentrated protein solution then may be cooled for furtherprocessing as described below, preferably to a temperature of about 25°to about 40° C.

Depending on the temperature employed in the concentration step andoptional diafiltration step and whether or not a pasteurization step iseffected, the concentrated protein solution may be warmed to atemperature of at least about 20°, and up to about 60° C., preferablyabout 25° to about 40° C., to decrease the viscosity of the concentratedprotein solution to facilitate performance of the subsequent dilutionstep and micelle formation. The concentrated protein solution should notbe heated beyond a temperature above which micelle formation does notoccur on dilution by chilled water.

The concentrated protein solution resulting from the concentration step,and optional diafiltration step, optional colour removal step, optionalpasteurization step and optional defatting step, then is diluted toeffect micelle formation by mixing the concentrated protein solutionwith chilled water having the volume required to achieve the degree ofdilution desired. Depending on the proportion of canola protein desiredto be obtained by the micelle route and the proportion from thesupernatant, the degree of dilution of the concentrated protein solutionmay be varied. With lower dilution levels, in general, a greaterproportion of the canola protein remains in the aqueous phase.

When it is desired to provide the greatest proportion of the protein bythe micelle route, the concentrated protein solution is diluted by about5 fold to about 25 fold, preferably by about 10 fold to about 20 fold.

The chilled water with which the concentrated protein solution is mixedhas a temperature of less than about 15° C., generally about 1° to about15° C., preferably less than about 10° C., since improved yields ofprotein isolate in the form of protein micellar mass are attained withthese colder temperatures at the dilution factors used.

In a batch operation, the batch of concentrated protein solution isadded to a static body of chilled water having the desired volume, asdiscussed above. The dilution of the concentrated protein solution andconsequential decrease in ionic strength causes the formation of acloud-like mass of highly associated protein molecules in the form ofdiscrete protein droplets in micellar form. In the batch procedure, theprotein micelles are allowed to settle in the body of chilled water toform an aggregated, coalesced, dense, amorphous sticky gluten-likeprotein micellar mass (PMM). The settling may be assisted, such as bycentrifugation. Such induced settling decreases the liquid content ofthe protein micellar mass, thereby decreasing the moisture contentgenerally from about 70% by weight to about 95% by weight to a value ofgenerally about 50% by weight to about 80% by weight of the totalmicellar mass. Decreasing the moisture content of the micellar mass inthis way also decreases the occluded salt content of the micellar mass,and hence the salt content of dried isolate.

Alternatively, the dilution operation may be carried out continuously bycontinuously passing the concentrated protein solution to one inlet of aT-shaped pipe, while the diluting water is fed to the other inlet of theT-shaped pipe, permitting mixing in the pipe. The diluting water is fedinto the T-shaped pipe at a rate sufficient to achieve the desireddegree of dilution of the concentrated protein solution.

The mixing of the concentrated protein solution and the diluting waterin the pipe initiates the formation of protein micelles and the mixtureis continuously fed from the outlet from the T-shaped pipe into asettling vessel, from which, when full, supernatant is permitted tooverflow. The mixture preferably is fed into the body of liquid in thesettling vessel in a manner which minimizes turbulence within the bodyof liquid.

In the continuous procedure, the protein micelles are allowed to settlein the settling vessel to form an aggregated, coalesced, dense,amorphous, sticky, gluten-like protein micellar mass (PMM) and theprocedure is continued until a desired quantity of the PMM hasaccumulated in the bottom of the settling vessel, whereupon theaccumulated PMM is removed from the settling vessel. In lieu of settlingby sedimentation, the PMM may be separated continuously bycentrifugation.

The combination of process parameters of concentrating of the proteinsolution to a preferred protein content of at least about 200 g/L andthe use of a dilution factor of about 10 to about 20, result in higheryields, often significantly higher yields, in terms of recovery ofprotein in the form of protein micellar mass from the original mealextract, and much purer isolates in terms of protein content thanachieved using any of the known prior art protein isolate formingprocedures discussed in the aforementioned US patents.

By the utilization of a continuous process for the recovery of canolaprotein product as compared to the batch process, the initial proteinextraction step can be significantly reduced in time for the same levelof protein extraction and significantly higher temperatures can beemployed in the extraction step. In addition, in a continuous operation,there is less chance of contamination than in a batch procedure, leadingto higher product quality and the process can be carried out in morecompact equipment.

The settled canola protein product is separated from the residualaqueous phase or supernatant, such as by decantation of the residualaqueous phase from the settled mass or by centrifugation. The PMM may beused in the wet form or may be dried, by any convenient technique, suchas spray drying or freeze drying, to a dry form. The dry PMM has a highprotein content, in excess of about 90 wt % protein, preferably at leastabout 100 wt % protein (calculated as Kjeldahl N×6.25), and issubstantially undenatured (as determined by differential scanningcalorimetry). The dry PMM isolated from fatty oil seed meal also has alow residual fat content, when the procedures of U.S. Pat. Nos.5,844,086 and 6,005,076 are employed as necessary, which may be belowabout 1 wt %.

As is known from U.S. Pat. No. 7,662,922 (WO 03/086760), assigned to theassignee hereof and the disclosure of which is incorporated herein byreference, the PMM consists predominantly of a 7S canola protein havinga protein component content of about 60 to 98 wt % of 7S protein, about1 to about 15 wt % of 12S protein and 0 to about 25 wt % of 2S protein.

The supernatant from the PMM formation and settling step containssignificant amounts of canola protein, not precipitated in the dilutionstep, and is processed to recover canola protein isolate therefrom. Asdescribed in the aforementioned U.S. Pat. No. 7,662,922, the canolaprotein isolate derived from the supernatant consists predominantly of2S canola protein having a protein component content of about 60 toabout 95 wt % of 2S protein, about 5 to about 40 wt % of a 7S proteinand 0 to about 5 wt % of 12S protein.

In the present invention, a calcium salt, preferably calcium chloride,is added to the supernatant, which may first be concentrated orpartially concentrated, in the manner described below, to provide aconductivity of about 5 mS to about 30 mS, preferably 8 mS to about 10mS. The calcium chloride added to the supernatant may be in any desiredform, such as a concentrated aqueous solution thereof.

The addition of the calcium chloride has the effect of depositing phyticacid, in the form of phytate, from the supernatant and retaining bothglobulin and albumen fractions of the supernatant. The deposited phytateis recovered from the supernatant, such as by centrifugation and/orfiltration, to leave a clear solution. If desired, the deposited phytatemay not be removed, in which case the further processing results in aproduct having a higher phytate content.

The pH of the clear solution then is adjusted to a value of about 2.0 toabout 4.0, preferably about 2.9 to 3.2. The pH adjustment may beeffected in any convenient manner, such as by the addition ofhydrochloric acid. If desired, the acidification step may be omittedfrom the various options described herein.

The pH-adjusted clear solution, if not already concentrated, isconcentrated to increase the protein concentration thereof. Suchconcentration is effected using any convenient selective membranetechnique, such as ultrafiltration, using membranes with a suitablemolecular weight cut-off permitting low molecular weight species,including the salt, carbohydrates, pigments and other low molecularweight materials extracted from the protein source material, to passthrough the membrane, while retaining a significant proportion of thecanola protein in the solution. Ultrafiltration membranes having amolecular weight cut-off of about 3,000 to 100,000 daltons, preferablyabout 5,000 to about 10,000 daltons, having regard to differing membranematerials and configuration, may be used. Concentration of thesupernatant in this way also reduces the volume of liquid required to bedried to recover the protein. The supernatant generally is concentratedto a protein concentration of at least about 50 g/L, preferably about 50to about 500 g/L, more preferably about 100 to about 150 g/L, prior todrying. Such concentration operation may be carried out in a batch modeor in a continuous operation, as described above for the proteinsolution concentration step.

Where the supernatant is partially concentrated prior to the addition ofthe calcium salt and fully concentrated after removal of theprecipitate, the supernatant is first concentrated to a proteinconcentration of about 50 g/L or less, and, after removal of theprecipitate, then is concentrated to a concentration of at least about50 g/L, preferably about 50 to about 500 g/L, more preferably about 100to about 250 g/L.

In one embodiment of the invention, the calcium salt may be added in twostages. In this embodiment, a small amount of calcium is added to thesupernatant to provide a conductivity of about 1 mS to about 3.5 mS,preferably about 1 mS to about 2 mS, which is insufficient to cause theformation of a precipitate.

The resulting solution is acidified and partially concentrated under theconditions described above. The balance of the calcium salt is added tothe partially concentrated solution to provide a conductivity of about 4mS to about 30 mS, preferably about 4 to about 10 mS, to result in theformation of a precipitate. The precipitate then is removed. Theresulting clear solution then is concentrated under the conditionsdescribed above.

The concentrated supernatant then may be subjected to a diafiltrationstep using water, saline or acidified water. The water may be at itsnatural pH equal to the protein solution being diafiltered or any pH inbetween. Such diafiltration may be effected using from about 2 to about20 volumes of diafiltration solution, such as pH3 or natural pH water,preferably about 5 to about 10 volumes of diafiltration solution. In thediafiltration operation, further quantities of contaminants are removedfrom the aqueous supernatant by passage through the membrane with thepermeate. The diafiltration operation may be effected until nosignificant further quantities of contaminants and visible colour arepresent in the permeate. Such diafiltration may be effected using thesame membrane as for the concentration step. However, if desired, thediafiltration may be effected using a separate membrane, such as amembrane having a molecular weight cut-off in the range of about 3,000to about 100,000 daltons, preferably about 5,000 to about 10,000daltons, having regard to different membrane materials andconfiguration.

The concentration step and the diafiltration step are effected herein insuch a manner that the canola protein isolate subsequently recoveredcontains less than about 90 wt % protein (N×6.25), such as at leastabout 60 wt % protein (N×6.25). As discussed above, it is well knownthat concentration and diafiltration processes allow for removal ofwater and small molecular weight contaminants from a solution. Bypartially concentrating and/or diafiltering a solution, it is possibleto only partially remove contaminants, thereby resulting in a proteinproduct with lower levels of purity once the drying step has beeneffected.

An antioxidant may be present in the diafiltration medium during atleast part of the diafiltration step. The antioxidant may be anyconvenient antioxidant, such as sodium sulfite or ascorbic acid. Thequantity of antioxidant employed in the diafiltration medium depends onthe materials employed and may vary from about 0.01 to about 1 wt %,preferably about 0.05 wt %. The antioxidant serves to inhibit oxidationof phenolics present in the concentrated canola protein isolatesolution.

The concentrated and optionally diafiltered protein solution may besubjected to a colour removal operation as an alternative to the colourremoval operation described above. Powdered activated carbon may be usedherein as well as granulated activated carbon (GAC). Another materialwhich may be used as a colour adsorbing agent is polyvinyl pyrrolidone.

The colour adsorbing agent treatment step may be carried out under anyconvenient conditions, generally at the ambient temperature of thecanola protein solution. For powdered activated carbon, an amount ofabout 0.025% to about 5% w/v, preferably about 0.05% to about 2% w/v,may be used. Where polyvinylpyrrolidone is used as the colour adsorbingagent, an amount of about 0.5% to about 5% w/v, preferably about 2% toabout 3% w/v, may be used. The colour adsorbing agent may be removedfrom the canola protein solution by any convenient means, such as byfiltration.

The concentrated and optionally diafiltered and optionally colourremoval treated protein solution is dried by any convenient technique,such as spray drying or freeze drying, to a dry form. The canola proteinproduct is low in phytic acid content, generally less than about 1.5% byweight.

The canola protein product produced herein contains both albumen andglobulin fractions and is soluble in an acidic aqueous environment,making the product ideal for incorporation into beverages, bothcarbonated and uncarbonated, to provide protein fortification thereto.Such beverages have a wide range of acidic pH values, ranging from about2.5 to about 5. The canola protein product provided herein may be addedto such beverages in any convenient quantity to provide proteinfortification to such beverages, for example, at least about 5 g of thecanola protein product per 12 fluid ounce quantity. The added canolaprotein product dissolves in the beverage and does not impair theclarity of the beverage. The canola protein product may be blended withdried beverage prior to reconstitution of the beverage by dissolution inwater.

EXAMPLES Example 1

This Example describes the production of a novel canola protein productof less than 90% protein by weight in accordance with one embodiment ofthe invention.

“a” kg of canola meal was added to “b” L of “c” M NaCl solution atambient temperature and agitated for 30 minutes to provide an aqueousprotein solution. The residual canola meal was removed and the resultingprotein solution was partially clarified by centrifugation to produce“d” L of partially clarified protein solution having a protein contentof “e” % by weight. The partially clarified protein solution wasfiltered to further clarify the solution, resulting in a solution ofvolume “f” having a protein content of “g” by weight.

The “h” L of protein extract solution was reduced in volume to “i” L byconcentration on a polyethersulfone (PES) membrane having a molecularweight cutoff of “j” daltons. The resulting concentrated proteinsolution had a protein content of “k” % by weight.

The concentrated solution at “1”° C. was diluted “m” into cold RO waterhaving a temperature “n”° C. A white cloud formed immediately and theprecipitated, viscous, sticky mass (PMM) was recovered by centrifugationin a yield of “o” wt % of the filtered protein solution. The dried PMMderived protein was found to have a protein content of “p” % (N×6.25)d.b. The product was given a designation “q” C307C.

The parameters “a” to “q” for one is set forth in the following Table 1:

TABLE 1 q BW-SD092-J06-08A a 100 b 1000 c 0.15 d 755 e 1.29 f 792 g 1.20h 792 i 37.72 j 100,000 k 19.36 l 30 m 1:15 n 4 o 43.5 p 101 qBW-SD092-J06-08A

The calcium chloride addition described in the present invention wasthen carried out on the supernatant from the PMM deposition.

“r” L of supernatant was adjusted to a conductivity of “s” ms by theaddition of calcium chloride from a concentrated solution thereof. Thissolution is then centrifuged and/or filtered to remove precipitatedphytate material, resulting in “t” L of a reduced phytate content,clarified protein solution at a concentration of “u” % by weight. Thereduced phytate content, clarified supernatant was then adjusted to pH“v” by the addition of HCl and reduced in volume to “w” L byultrafiltration using a polyethersulfone (PBS) membrane having amolecular weight cut-off of ‘x’ Daltons. The concentrate was thendiafiltered on the same membrane with “y” L of water. The diafilteredconcentrate contained “z” % protein by weight. With the additionalprotein recovered from the supernatant, the overall protein recovery ofthe filtered protein solution was “aa” wt %. The “ab” L of concentratewas subjected to a colour reduction step by passing it through a “ac” Lbed volume column of granular activated carbonate of “ad” BV/hr at a pH3. The “ae” L of (GAC) treated solution having reduced colour and aprotein content of “at” % by weight was then spray dried and givendesignation “q” C200CaC and had a protein content of “ah”.

The parameters ‘r’ to ‘ah’ for one run are set forth in the followingtable.

TABLE 2 q BW-SD092-J06-08A r 578.5 s 8 t 570 u 0.63 v 3.0 w 25.86 x10,000 y 150 z 8.98 aa 24 ab 25.86 ac 5.7 ad 5 ae 28.86 af 4.30 ah 88.57

The dried canola protein product was added to water to make a solutionwith a protein content of 3.2 w/v %. The solution was mixed untilsolubilized and then analyzed on a HunterLab ColorQuest XE instrumentfor colour and clarity. Colour and clarity values for the resolubilizedsamples at pH 3 are in Table 3.

TABLE 3 Protein Solution Solution Content pH Protein “L” “a” “b” % HazeBW-SD092- 88.6% 3.08 3.2% 97.77 −6.80 35.92 4.5% J06-08A BW-SD092- 93.5%3.03 3.2% 94.03 −7.92 37.10 0.5% A06-09A BW-SD092- 93.3% 3.2 3.2% 92.58−6.45 38.75 3.1% C23-09A

The colour and clarity readings provided in Table 3 for the concentrateare comparable to those of a similar product of higher protein content.

Example 2

This Example describes the production of a novel canola protein productof less than 90% protein by weight in accordance with another embodimentof the invention.

“a” kg of canola meal was added to “b” L of “c” M NaCl solution atambient temperature and agitated for 30 minutes to provide an aqueousprotein solution. The residual canola meal was removed and the resultingprotein solution was partially clarified by centrifugation to produce“d” L of partially clarified protein solution having a protein contentof “e” % by weight. The partially clarified protein solution wasfiltered to further clarify, resulting in a solution of volume “f” Lhaving a protein content of “g” % by weight.

The “h” L of clarified protein extract solution was reduced in volume to“i” L by concentration on a polyethersulfone (PES) membrane having amolecular weight cutoff of “j” daltons. The resulting concentratedprotein solution had a protein content of “k” % by weight.

The concentrated solution at “1”° C. was diluted “m” into cold RO waterhaving a temperature “n”° C. A white cloud formed immediately and theprecipitated, viscous, sticky mass (PMM) was recovered by centrifugationin a yield of “o” wt % of the filtered protein solution. The PMM wasremoved from the supernatant and dried. The dried PMM derived proteinwas found to have a protein content of “p” % (N×6.25) d.b. The productwas given a designation “q” C307C.

“r” L supernatant was adjusted to a conductivity “s” ms by the additionof calcium chloride from a concentrated solution. This solution was thencentrifuged and/or filtered to remove precipitated phytate material,resulting in “t” L of a reduced phytate content, clarified proteinsolution at a concentration of “u” % by weight. The reduced phytatecontent, clarified supernatant was then adjusted to pH “v” by theaddition of HCl and reduced in volume to “w” L by ultrafiltration usinga polyethersulfone (PES) membrane having a molecular weight cut-off of‘x’ Daltons. At volume reduction points 3, 5, and 7, 200 ml samples ofthe retentate were taken and dried. The dried canola protein product wasadded to sufficient RO water to make a solution with a protein contentof 3.2 w/v %. The solution was mixed until fully solubilized and thenanalyzed on a HunterLab ColorQuest XE instrument for colour and clarity.Dried samples were analyzed for protein content and clarity uponresolubilization under acidic conditions. Results are set forth in thefollowing Table 4:

TABLE 4 Colour Analysis % Protein DB “L” “a” “b” Haze (%) VRF 3 70%95.23 −7.54 34.68 0.0% VRF 5 78% 94.63 −7.84 38.13 1.5% VRF 7 81% 94.18−8.07 40.90 1.9%

The parameters ‘a’ to ‘x’ for one run are set forth in the followingTable 5:

TABLE 5 q BW-SD092-A06-09A a 150 b 1500 c 0.15 d 1075.2 e 1.62 f 1047 g1.47 h 1047 i 69.12 j 100,000 k 18.68 l 30 m 1:15 n 4 o 43.5 p 105 r1058.1 s 8 t 974 u 0.63 v 3.0 w 48 x 10,000

The colour and clarity readings provided in Table 4 are comparable tothose of a similar product of high protein content, as can be seen bycomparison with the isolates in Table 3.

SUMMARY OF THE DISCLOSURE

In summary of this disclosure, a 2S-predominated canola protein productis produced of equivalent properties to the 2S-predominated canolaprotein isolate produced in the aforementioned U.S. patent applicationSer. No. 12/542,922. Modifications are possible within the scope of theinvention.

What we claim is:
 1. A process of preparing a canola protein product,which comprises: adding a calcium salt to supernatant from theprecipitation of a canola protein micellar mass to provide aconductivity of about 5 mS to about 30 mS to form a calcium phytateprecipitate, removing precipitated calcium phytate from the resultingsolution to provide a clear solution, adjusting the pH of the clearsolution to about 2.0 to about 4.0, concentrating the pH-adjusted clearsolution to a protein content of at least about 50 g/L to produce aclear concentrated canola protein solution, optionally diafiltering theclear concentrated canola protein solution, optionally effecting acolour removal step, and drying the concentrated protein solution toproduce a dried canola protein product, wherein said concentrationand/or optional diafiltration step are effected in such manner that thedried canola protein product contains about 60 to less than 90 wt %(N×6.25) protein on a dry weight basis.
 2. A process of preparing acanola protein product, which comprises: partially concentrating thesupernatant from the precipitation of a canola protein micellar mass toa concentration of about 50 g/L or less, adding a calcium salt to thepartially concentrated supernatant to provide a conductivity of about 2mS to about 30 mS to precipitate calcium phytate from the partiallyconcentrated supernatant, removing the precipitated calcium phytate fromthe resulting solution to provide a clear solution, adjusting the pH ofthe clear solution to about 2.0 to about 4.0, concentrating thepH-adjusted clear solution to a protein content of at least about 50 g/Lto produce a clear concentrated canola protein solution, optionallydiafiltering the clear concentrated canola protein solution, optionallyeffecting a colour removal step, and drying the concentrated proteinsolution to produce a dried canola protein product, wherein saidconcentration and/or optional diafiltration step are effected in suchmanner that the dried canola protein product contains about 60 to lessthan 90 wt % (N×6.25) protein on a dry weight basis.
 3. A process ofpreparing a canola protein product, which comprises: concentratingsupernatant from the precipitation of a canola protein micellar mass toa protein content of at least about 50 g/ to produce a concentratedsupernatant, adding a calcium salt to the concentrated supernatant toprovide a conductivity of about 2 to about 30 mS to cause precipitationof calcium phytate, removing calcium phytate from the resulting solutionto provide a clear solution, adjusting the pH of the clear solution toabout 2.0 to about 4.0, optionally diafiltering the clear pH-adjustedsolution, optionally effecting a colour removal step, and drying theclear optionally pH-adjusted protein solution to produce a dried canolaprotein product, wherein said concentration and/or optionaldiafiltration step are effected in such manner that the dried canolaprotein product contains about 60 to less than 90 wt % (N×6.25) proteinon a dry weight basis.
 4. A canola protein product produced by theprocess of any one of claims 1 to
 3. 5. An acidic solution havingdissolved therein the canola protein product of claim
 4. 6. The processof claim 1 wherein the calcium salt is calcium chloride.
 7. The processof claim 1 wherein the conductivity is from about 8 to about 10 mS. 8.The process of claim 1 wherein the pH of the clear solution is adjustedto a pH of about 2.9 to about 3.2.
 9. The process of claim 1 wherein thepH-adjusted clear solution is concentrated to a concentration of about50 to about 500 g/L.
 10. The process of claim 9 wherein theconcentration is about 100 to about 350 g/L.
 11. The process of claim 1wherein said colour removal step is a granular activated carbontreatment.
 12. The process of claim 2 wherein the calcium salt iscalcium chloride.
 13. The process of claim 2 wherein the conductivity isfrom about 4 to about 10 mS.
 14. The process of claim 2 wherein the pHof the clear solution is adjusted to a pH of about 2.9 to about 3.2. 15.The process of claim 2 wherein the pH-adjusted clear solution isconcentrated to a concentration of about 100 to about 500 g/L.
 16. Theprocess of claim 15 wherein the concentration is about 100 to about 350g/L.
 17. The process of claim 2 wherein said colour removal step is agranular activated carbon treatment.
 18. The process of claim 3 whereinthe supernatant is concentrated to a concentration of about 100 to about500 g/L.
 19. The process of claim 18 wherein the calcium salt is calciumchloride.
 20. The process of claim 3 wherein the calcium salt is calciumchloride.
 21. The process of claim 3 wherein the conductivity is fromabout 4 to about 10 mS.
 22. The process of claim 3 wherein the pH of theclear solution is adjusted to a pH of about 2.9 to about 3.2.
 23. Theprocess of claim 3 wherein said colour removal step is a granularactivated carbon treatment.
 24. A process of preparing a canola proteinproduct, which comprises: adding a calcium salt to supernatant from theprecipitation of a canola protein micellar mass to provide aconductivity of about 5 mS to about 30 mS to form a calcium phytateprecipitate, removing precipitated calcium phytate from the resultingsolution to provide a clear solution, adjusting the pH of the clearsolution to about 2.0 to about 4.0, concentrating the pH-adjusted clearsolution to a protein content of at least about 50 g/L produce a clearconcentrated canola protein solution, diafiltering the clearconcentrated canola protein solution with volumes of pH 3 water,optionally effecting a colour removal step, and drying the concentratedprotein solution to produce a dried canola protein product, wherein saidconcentration and/or optional diafiltration step are effected in suchmanner that the dried canola protein product contains about 60 to lessthan 90 wt % (N×6.25) protein on a dry weight basis.
 25. A process ofpreparing a canola protein product, which comprises: adding calciumchloride to supernatant from the precipitation of a protein micellesmass to provide a concentration of the conductivity of about 8 to about10 mS to form a calcium phytate precipitate, removing the precipitatedcalcium phytate from the resulting solution to provide a clear solution,adjusting the pH of the clear solution to a pH of about 2.9 to about3.2, concentrating the pH-adjusted clear solution to a concentration ofabout 50 to about 500 g/L to produce a clear concentrated canola proteinsolution, optionally diafiltering the clear concentrated canola proteinsolution, optionally effecting a colour removal step, and drying theconcentrated protein solution to produce a dried canola protein product,wherein the concentrated and/or optional diafiltration step are effectedin such manner that the dried canola protein product contains about 60to less than 90 wt % (N×6.25) protein on a dry weight basis.
 26. Aprocess of preparing a canola protein product, which comprises:partially concentrating the supernatant from the precipitation of acanola protein micellar mass to a concentration of about 50 g/L or less,adding a calcium salt to the partially concentrated supernatant toprovide a conductivity of about 2 mS to about 30 mS to precipitatecalcium phytate from the partially concentrated supernatant, removingthe precipitated calcium phytate from the resulting solution to providea clear solution, adjusting the pH of the clear solution to about 2.0 toabout 4.0, concentrating the pH-adjusted clear solution to a proteincontent of at least about 50 g/L to produce a clear concentrated canolaprotein solutions, diafilterinq the clear concentrated canola proteinsolution with volumes of pH 3 water, optionally effecting a colourremoval step, and drying the concentrated protein solution to produce adried canola protein product, wherein said concentration and/or optionaldiafiltration step are effected in such manner that the dried canolaprotein product contains about 60 to less than 90 wt % (N×6.25) proteinon a dry weight basis.
 27. A process of preparing a canola proteinproduct, which comprises: partially concentrating the supernatant fromthe precipitation of a canola protein micellar mass to a concentrationof about 50 g/L or less, adding calcium chloride to a partiallyconcentrated supernatant to provide a conductivity of about 4 to about10 mS to precipitate calcium phytate from the partially concentratedsupernatant, removing the precipitated calcium phytate from theresulting solution to provide a clear solution, adjusting the pH of theclear solution is adjusted to a pH of about 2.9 to about 3.2,concentrating the pH-adjusted clear solution to a concentration of about50 to about 500 g/L to provide a clear concentrated canola proteinsolution, optionally effecting a colour removal step, and drying theconcentrated protein solution to produce a dried canola protein product,wherein said concentrated and/or optional diafiltration step areeffected in such manner that the dried canola protein product containsabout 60 to less than 90 wt % (N×6.25) protein on a dry weight basis.28. A process of preparing a canola protein product, which comprises:concentrating supernatant from the precipitation of a canola proteinmicellar mass to a protein content of at least about 50 g/ to produce aconcentrated supernatant, adding a calcium salt to the concentratedsupernatant to provide a conductivity of about 2 to about 30 mS to causeprecipitation of calcium phytate, removing calcium phytate from theresulting solution to provide a clear solution, adjusting the pH of theclear solution to about 2.0 to about 4.0, diafiltering the clearpH-adjusted solution with volumes of pH 3 water, optionally effecting acolour removal step, and drying the clear optionally pH-adjusted proteinsolution to produce a dried canola protein product, wherein saidconcentration and/or optional diafiltration step are effected in suchmanner that the dried canola protein product contains about 60 to lessthan 90 wt % (N×6.25) protein on a dry weight basis.
 29. A process ofpreparing a canola protein product, which comprises: concentratingsupernatant from the precipitation of a canola protein micellar mass toa protein content of about 50 g/L to about 500 g/L to produce aconcentrated supernatant, adding calcium chloride to the concentratedsupernatant to provide a conductivity from about 4 to about 10 mS tocause precipitation of calcium phytate, removing calcium phytate fromthe resulting solution to provide a clear solution, adjusting the pH ofthe clear solution to a pH of about 2.9 to about 3.2, optionallydiafiltering the clear pH-adjusted solution, optionally effecting acolour removal step, and drying the clear optionally pH-adjusted proteinsolution to produce a dried canola protein product, wherein saidconcentrated and/or optional diafiltration step are effected in suchmanner that the dried canola protein product contains about 60 to lessthan 90 wt % (N×6.25) protein on a dry weight basis.